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 $EA31/59953:   Main IRQ Entry Point

EA31: 20 EA FF  <A HREF="BJSR.HTM">JSR</A> <A HREF="ROMFFEA.HTM">$FFEA</A>     ; Increment Real-Time Clock
EA34: A5 CC     <A HREF="BLDA.HTM">LDA</A> <A HREF="ZPCC.HTM">$CC</A>       ; Flag: Cursor blink
EA36: D0 29     <A HREF="BBNE.HTM">BNE</A> $EA61
EA38: C6 CD     <A HREF="BDEC.HTM">DEC</A> <A HREF="ZPCD.HTM">$CD</A>       ; Timer: Count down for Cursor blink toggle
EA3A: D0 25     <A HREF="BBNE.HTM">BNE</A> $EA61
EA3C: A9 14     <A HREF="BLDA.HTM">LDA</A> #$14
EA3E: 85 CD     <A HREF="BSTA.HTM">STA</A> <A HREF="ZPCD.HTM">$CD</A>       ; Timer: Count down for Cursor blink toggle
EA40: A4 D3     <A HREF="BLDY.HTM">LDY</A> <A HREF="ZPD3.HTM">$D3</A>       ; Cursor Column on current Line
EA42: 46 CF     <A HREF="BLSR.HTM">LSR</A> <A HREF="ZPCF.HTM">$CF</A>       ; Flag: Cursor Status
EA44: AE 87 02  <A HREF="BLDX.HTM">LDX</A> <A HREF="ZP0287.HTM">$0287</A>     ; Background Color under Cursor
EA47: B1 D1     <A HREF="BLDA.HTM">LDA</A> (<A HREF="ZPD1.HTM">$D1</A>),Y   ; Pointer: Current Screen Line Address
EA49: B0 11     <A HREF="BBCS.HTM">BCS</A> $EA5C
EA4B: E6 CF     <A HREF="BINC.HTM">INC</A> <A HREF="ZPCF.HTM">$CF</A>       ; Flag: Cursor Status
EA4D: 85 CE     <A HREF="BSTA.HTM">STA</A> <A HREF="ZPCE.HTM">$CE</A>       ; Character under Cursor while Cursor Inverted
EA4F: 20 24 EA  <A HREF="BJSR.HTM">JSR</A> <A HREF="ROMEA24.HTM">$EA24</A>     ; Syncronise Color Pointer
EA52: B1 F3     <A HREF="BLDA.HTM">LDA</A> (<A HREF="ZPF3.HTM">$F3</A>),Y   ; Pointer: Current Color RAM Location
EA54: 8D 87 02  <A HREF="BSTA.HTM">STA</A> <A HREF="ZP0287.HTM">$0287</A>     ; Background Color under Cursor
EA57: AE 86 02  <A HREF="BLDX.HTM">LDX</A> <A HREF="ZP0286.HTM">$0286</A>     ; Current Character Color code
EA5A: A5 CE     <A HREF="BLDA.HTM">LDA</A> <A HREF="ZPCE.HTM">$CE</A>       ; Character under Cursor while Cursor Inverted

Jump from $EA49:

EA5C: 49 80     <A HREF="BEOR.HTM">EOR</A> #$80
EA5E: 20 1C EA  <A HREF="BJSR.HTM">JSR</A> <A HREF="ROMEA13.HTM">$EA1C</A>     ; Print To Screen

Jump from $EA36, $EA3A:

EA61: A5 01     <A HREF="BLDA.HTM">LDA</A> <A HREF="ZP01.HTM">$01</A>       ; 6510 On-chip 8-bit Input/Output Register
EA63: 29 10     <A HREF="BAND.HTM">AND</A> #$10
EA65: F0 0A     <A HREF="BBEQ.HTM">BEQ</A> $EA71
EA67: A0 00     <A HREF="BLDY.HTM">LDY</A> #$00
EA69: 84 C0     <A HREF="BSTY.HTM">STY</A> <A HREF="ZPC0.HTM">$C0</A>       ; Tape Motor Switch
EA6B: A5 01     <A HREF="BLDA.HTM">LDA</A> <A HREF="ZP01.HTM">$01</A>       ; 6510 On-chip 8-bit Input/Output Register
EA6D: 09 20     <A HREF="BORA.HTM">ORA</A> #$20
EA6F: D0 08     <A HREF="BBNE.HTM">BNE</A> $EA79

Jump from $EA65:

EA71: A5 C0     <A HREF="BLDA.HTM">LDA</A> <A HREF="ZPC0.HTM">$C0</A>       ; Tape Motor Switch
EA73: D0 06     <A HREF="BBNE.HTM">BNE</A> $EA7B
EA75: A5 01     <A HREF="BLDA.HTM">LDA</A> <A HREF="ZP01.HTM">$01</A>       ; 6510 On-chip 8-bit Input/Output Register
EA77: 29 1F     <A HREF="BAND.HTM">AND</A> #$1F

Jump from $EA6F:

EA79: 85 01     <A HREF="BSTA.HTM">STA</A> <A HREF="ZP01.HTM">$01</A>       ; 6510 On-chip 8-bit Input/Output Register

Jump from $EA73:

EA7B: 20 87 EA  <A HREF="BJSR.HTM">JSR</A> <A HREF="ROMEA87.HTM">$EA87</A>     ; Scan Keyboard
EA7E: AD 0D DC  <A HREF="BLDA.HTM">LDA</A> <A HREF="CIA113.HTM">$DC0D</A>     ; CIA1: Interrupt (IRQ) Control Register

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Kernal-Reference:

 LDA $EA60   : <A HREF="ROME3A2.HTM">$E3A8</A>

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